Multi-Layer Heat Assembly For A Drug Delivery Device

ABSTRACT

In various embodiments, an ophthalmic injection device may include a dispensing chamber to hold a substance (e.g., a drug) to be injected into an eye, a thermal feedback layer with at least one thermal sensor, and a temperature control layer to apply or remove heat from the dispensing chamber. In some embodiments, the thermal feedback layer and the temperature control layer may be coupled to each other and/or coupled to the dispensing chamber. In some embodiments, at least one of the thermal sensors may be secured between the temperature control layer and the dispensing chamber using a thermal adhesive.

PRIORITY

This application claims the benefit of priority of U.S. ProvisionalPatent Application Ser. No. 61/175,813 titled “Multi-layer Heat Assemblyfor a Drug Delivery Device”, filed on May 6, 2009, whose inventor isCesario Dos Santos, which is hereby incorporated by reference in itsentirety as though fully and completely set forth herein.

This application also claims the benefit of priority of U.S. ProvisionalPatent Application Ser. No. 61/289,467 titled “Phase Transition DrugDelivery System”, filed on Dec. 23, 2009, whose inventors are CesarioDos Santos and Michael Gelvin, which is hereby incorporated by referencein its entirety as though fully and completely set forth herein.

FIELD OF THE INVENTION

The present invention generally pertains to temperature control devices.More particularly, but not by way of limitation, the present inventionpertains to temperature control devices for ophthalmic injections.

DESCRIPTION OF THE RELATED ART

Many diseases of the eye can be treated by injecting a drug into an eye.Injecting a drug into the eye may require control of both the volume andthe temperature of the drug to avoid complications. For example, volumecontrol may be important to avoid excessive pressure build-up in theeye. In addition, temperature of the drug may be adjusted to control,for example, a form of the drug (e.g., heated to a liquid for insertion)and/or rate of absorption of the drug into the eye.

SUMMARY OF THE INVENTION

In various embodiments, an ophthalmic injection device may include adispensing chamber, a first thermal sensor coupled to the dispensingchamber, a temperature control layer coupled to the dispensing chamber,a second thermal sensor coupled to the dispensing chamber, and a firstprocessing device. The first processing device may be configured toreceive temperature information from the first and second thermalsensors and control the temperature control layer using the receivedtemperature information.

In some embodiments, the ophthalmic injection device may include asecond processing device coupled to the first thermal sensor. The secondprocessing device may be configured to send temperature information fromthe first thermal sensor (e.g., in digital form) to the first processingdevice (which may be located, for example, in the dispensing assembly ofthe ophthalmic injection device). In some embodiments, the firstprocessing device may receive temperature information directly from thesecond thermal sensor (e.g., in analog form) and may compare thetemperature information from the first thermal sensor (received from thefirst processing device) and the second thermal sensor to detecttemperature offsets between the two sensors.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, reference ismade to the following description taken in conjunction with theaccompanying drawings in which:

FIG. 1 illustrates a block diagram of an ophthalmic injection deviceincluding a dispensing assembly coupled to a tip segment, according toan embodiment;

FIG. 2 is one view of an ophthalmic injection device including adisposable tip segment and a dispensing assembly according to anembodiment;

FIG. 3 is another embodiment of a dispensing assembly;

FIG. 4 is a cross section view of another embodiment of a dispensingassembly;

FIG. 5 is a cross section view of a disposable tip segment and adispensing assembly, according to an embodiment;

FIGS. 6 a-c are schematic depictions of three different circuits thatmay be included in various embodiments;

FIGS. 7 a-7 c illustrate circuit diagrams of an embodiment incorporatingan additional thermal sensor;

FIGS. 8 a-8 c illustrate configurations for thermally coupling a thermalsensor to a hub, according to various embodiments;

FIGS. 9 a-9 c illustrate an embodiment of a thermal feedback layer and atemperature control layer for a tip segment;

FIGS. 10 a-c illustrates an embodiment utilizing different form factorsfor the thermal feedback layer and temperature control layer of the tipsegment;

FIGS. 11 a-b illustrate an embodiment with a second processing device toreceive temperature information from a first thermal sensor;

FIG. 12 illustrates a flowchart of an embodiment of a method forinjecting a substance into an eye;

FIG. 13 illustrates a flowchart of an embodiment of a method for usingtemperature information from thermal sensors coupled to a handpiece;

FIG. 14 illustrates coupling the inner dispenser assembly to an outersupport, according to an embodiment;

FIG. 15 illustrates another embodiment of the thermal feedback layer;and

FIGS. 16 a-d illustrate an example of assembling the thermal feedbacklayer in the dispenser assembly.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are intended to provide a further explanation of the presentinvention as claimed.

DETAILED DESCRIPTION OF THE EMBODIMENTS Incorporation by Reference

U.S. Patent Application Publication entitled “Dispensing Assembly ForOphthalmic Injection Device,” Publication No. 20070270744, Ser. No.11/832,364, by Bruno Dacquay, Cesario Dos Santos, James Foster, CaseyLind, Raffi Pinedjian, and Robert Sanchez filed Aug. 1, 2007 is herebyincorporated by reference in its entirety as though fully and completelyset forth herein.

FIG. 1 illustrates a block diagram of an ophthalmic injection device 100including a dispensing assembly 111 coupled to a tip segment 105. Insome embodiments, the tip segment 105 may include a dispensing chamber103 coupled to a thermal feedback layer 109 and a temperature controllayer 107. The thermal feedback layer 109 may include one or morethermal sensors (e.g., thermal sensors 115 and 117) that providetemperature information to a processing device 119 (which may be locatedin the dispensing assembly 111 or the tip segment 105). In someembodiments, the thermal sensors may include a thermistor, athermocouple, etc. and the temperature information may include, forexample, a temperature, a temperature gradient, or a change in voltage,current, resistance, etc. that is indicative of a temperature, change intemperature (e.g., a change in resistance on a thermistor), etc.“Dispensing assembly 111” is used herein to generally refer to thedispensing assembly of the ophthalmic injection device 100 andembodiments of the dispensing assembly are denoted herein by letterindicators (e.g., dispensing assembly 111 a in FIG. 2, dispensingassembly 111 b in FIG. 3, etc).

In some embodiments, first processing device 119 (and/or otherprocessing devices such as second processing device 901 shown in FIGS. 9a, 9 c, 10 a, 10 c, and 11 a) may be programmable to function to controlvarious components of the ophthalmic injection device 100. For example,the first processing device 119 may use temperature information receivedfrom the thermal sensors to regulate the temperature control layer 107(e.g., first processing device 119 may interface with the temperaturecontrol layer 107 to activate/deactivate a resistive element 121 on thetemperature control layer 107, increase/decrease a heat output of theresistive element 121, etc). In some embodiments, the resistive element121 of the temperature control layer 107 may include resistive tracesembedded in a flexible insulation layer that convert electrical currentinto heat or use electrical current to move heat. For example, theresistive traces may include resistive heater traces embedded in Kapton™and wrapped around the dispensing chamber 103 to heat the dispensingchamber 103 and a substance 123 in the dispensing chamber 103. Asanother example, the resistive element 121 may include a thermoelectricheat pump with a cool side of the heat pump placed in contact with thedispensing chamber 103 to cool the dispensing chamber 103 and asubstance 123 in the dispensing chamber 103. Other resistive elements121 are also contemplated. Once heated or cooled, the substance 123 inthe chamber 103 may be injected into an eye 131 through the needle 101.

As seen in FIG. 1, the dispensing chamber 103 may be substantiallycylindrical with a first end face 125, a second end face 127, and a sideface 129 coupling the first end face 125 and the second end face 127.The thermal feedback layer 109 and temperature control layer 107 may beat least partially wrapped around the side face 129 and/or each other toapply or remove heat through the side face 129 and detect temperatureinformation associated with a temperature of a substance 123 in thechamber 103. For example, the thermal feedback layer 109 and temperaturecontrol layer 107 may cover a percentage of the area of the side face129 (e.g., >33% covered, >50% covered, >75% covered, etc). In someembodiments, the thermal feedback layer 109 and temperature controllayer 107 may be wrapped completely around (i.e., 360 degrees around)the side face 129 and/or may overlap itself.

FIG. 2 is an embodiment of an ophthalmic injection device 100 includinga disposable tip segment 105 and dispensing assembly 111 a. The tipsegment 105 may include a needle 101, a housing 215, and a light 275.While tip segment 105 is described throughout as “disposable”, in someembodiments, tip segment 105 may be used repeatedly. The dispensingassembly 111 a may include a housing 255, a switch 270, a lock mechanism265, and a threaded portion 260. In some embodiments, tip segment 105may be removably coupled to dispensing assembly 111 a (e.g., through athreaded portion on an interior surface of housing 215 that screws ontothe threaded portion 260 of dispensing assembly 111 a). In addition,lock mechanism 265 may secure tip housing 215 to dispensing assembly 111a. Other coupling mechanisms for the tip segment 105 and the dispensingassembly 111 a are also contemplated (e.g., adhesive, snaps, or aunitary housing for the tip segment 105 and dispensing assembly 111 a).Needle 101 may be configured to deliver a substance 123 from thedispensing chamber 103, such as a drug, into an eye 131. Needle 101 maybe configured with thermal characteristics that are conducive to drugdelivery. For example, needle 101 may be relatively short (e.g., on theorder of several millimeters) in length (for thermal purposes) tofacilitate proper delivery of a temperature controlled drug. In someembodiments, switch 270 may be used to activate the system or to turn ona temperature control layer 107.

FIG. 3 illustrates another embodiment of dispensing assembly 111 b.Dispensing assembly 111 b may include a button 308, a display 320, and ahousing 330. Disposable tip segment 105 may attach to end 340 ofdispensing assembly 111 b. In some embodiments, button 308 may activatea temperature control layer 107 or initiate actuation of a plunger.

FIG. 4 illustrates a cross section view of an embodiment of dispensingassembly 111 c. As seen in FIG. 4, power source 505, interface 517,actuator 515, and actuator shaft 510 may be located in housing 255. Thetop part of housing 255 may have a threaded portion 260. Lock mechanism265, switch 270, button 308, and indicators 306, 307 may all be locatedon housing 255. Power source 505 may provide power to tip segment 105connected to dispensing assembly 111 c. For example, power source 505may provide power to a temperature control layer 107 and/or thermalfeedback layer 109 located in the tip segment 105.

In some embodiments, actuator shaft 510 may be connected to and drivenby actuator 515. Actuator 515 may be a stepper motor or other type ofmotor that is capable of moving actuator shaft 510 precise distances. Insome embodiments, actuator shaft 510 may be connected via a mechanicallinkage to tip segment 105 that delivers a drug into an eye 131.Actuator 515 may be a stepper motor that may precisely move shaft 510 todeliver a precise quantity of drug into the eye 131. Actuator 515 may besecured to an interior surface of housing 255 by, for example, tabs thatengage the outer surface of actuator 515.

FIG. 5 illustrates a cross section view of a disposable tip segment 105interfacing with a dispensing assembly 111 d, according to anembodiment. In the embodiment shown in FIG. 5, tip segment 105 mayinclude assembly 555, temperature control layer 107, thermal feedbacklayer 109 (with thermal sensors 115 and 117), plunger interface 420,plunger 415, dispensing chamber housing 425, tip segment housing 215,needle 101, dispensing chamber 103, interface 530, and tip interfaceconnector 453. While thermal feedback layer 109 is shown under thetemperature control layer 107, this may be reversed (e.g., with thetemperature control layer 107 under the thermal feedback layer 109). Insome embodiments, the thermal feedback layer 109 and the temperaturecontrol layer 107 may be comprised in a single layer. In someembodiments, dispensing chamber housing 425 may have a recessed portionthat receives the temperature control layer 107 and/or the thermalfeedback layer 109. Dispensing assembly 111 d may include mechanicallinkage interface 545, actuator shaft 510, actuator 515, power source505, first processing device 119, dispensing assembly housing 255,interface 535, and dispensing assembly interface connector 553.

In some embodiments, assembly 555 may include a fuse 601 that is blownwhen a heat button is activated or according to instructions from afirst processing device 119 or second processing device 901 afterdisposable tip segment 105 is used (e.g., to prevent reuse of disposabletip segment 105). For example, as seen in FIGS. 6 c and 7 b, the fuse601 may be in parallel with the heating element 121 (which may notnecessarily be include in assembly 555). Other configurations of 555 arealso contemplated. For example, assembly 555 may include a memory devicethat stores information about the type of disposable tip segment 105,dosage information, temperature information, plunger movementinformation, or any other type of information that identifies acharacteristic of disposable tip segment 105 or a manner in whichdisposable tip segment 105 is operated. For example, assembly 555 mayinclude a hard-wired memory device, like an NAND (Not And electroniclogic gate) flash IC (integrated circuit), an RFID (Radio FrequencyIdentification) tag, a hard-wired wired circuit that can store arepresentation of data (e.g., a series of fuses and resistors connectedin parallel), or other type of device.

In some embodiments, plunger interface 420 may be located on one end ofplunger 415 in tip segment 105. The other end of plunger 415 may formone end of dispensing chamber 103. Plunger 415 may slide withindispensing chamber 103. The outer surface of plunger 415 may be fluidlysealed to the inner surface of dispensing chamber housing 425.Dispensing chamber housing 425 may surround the dispensing chamber 103(both of which may have a cylindrical shape). In some embodiments,needle 101 may be fluidly coupled to dispensing chamber 103. A substance123 (such as a drug) contained in dispensing chamber 103 may passthrough needle 101 and into an eye 131. Temperature control layer 107may at least partially surround dispensing chamber housing 425 and maybe connected to tip interface connector 453 through interface 530.Temperature control layer 107 may include a resistive element 121configured to heat or cool dispensing chamber housing 425 and anysubstance 123 contained in dispensing chamber 103 (which may be made ofa thermally conductive material such as copper, steel, etc). Othermaterials are also contemplated.

The components of tip segment 105, including dispensing chamber housing425, temperature control layer 107, and plunger 415 may be at leastpartially enclosed by tip segment housing 215. In some embodiments,plunger 415 may be sealed to the interior surface of dispensing chamberhousing 425. This seal may prevent contamination of a substance 123contained in dispensing chamber 103. This seal may be located at anypoint on plunger 415 or dispensing chamber housing 425.

In some embodiments, first processing device 119 and actuator 515 may beconnected by an interface to allow first processing device 119 tocontrol the operation of actuator 515. In addition, an interface betweenpower source 505 and first processing device 119 may allow firstprocessing device 119 to control operation of power source 505 (whichmay supply power to the first processing device 119 and/or actuator515). In such a case, first processing device 119 may control thecharging and the discharging of power source 505 when power source 505is a rechargeable battery.

In some embodiments, tip segment 105 may mate with or be attached todispensing assembly 111. As seen in FIG. 5, plunger interface 420 may belocated on a bottom surface of plunger 415 that mates with mechanicallinkage interface 545 located near a top surface of dispensing assemblyhousing 255. In addition, tip interface connector 453 may connect withdispensing assembly interface connector 553. When tip segment 105 isconnected to dispensing assembly 111 in this manner, actuator 515 andactuator shaft 510 may drive plunger 415 toward needle 101. A signal maypass between first processing device 119 and the thermal feedback layer109 or temperature control layer 107 through interface 535, dispensingassembly interface connector 553, tip interface connector 453, and/orinterface 530.

In operation, when tip segment 105 is connected to dispensing assembly111, first processing device 119 may control operation of actuator 515.When actuator 515 is actuated, actuator shaft 510 may move toward needle101. In turn, mechanical linkage interface 545, which may be mated withplunger interface 420, may move plunger 415 toward needle 101. Asubstance 123 located in dispensing chamber 103 may then be expelledthrough needle 101.

In some embodiments, first processing device 119 and/or secondprocessing device 901 may control the operation of temperature controllayer 107 based on temperature information received from the firstand/or second thermal sensors. For example, temperature control layer107 may include a heater and first processing device 119 may control theamount of current that is sent to the heater based on the receivedtemperature information. In some embodiments, the temperatureinformation may indicate an approximate temperature of the dispensingchamber 103 and the current may be adjusted to increase or decrease thetemperature to a desired temperature. For example, as the current levelincreases, the temperature of a resistive element 121 in the heater mayincrease. In some embodiments, the current may be discontinued if thetemperature information indicates a desired temperature has beenobtained. Temperature control layer 107 may be in direct thermal contactwith dispensing chamber housing 425 (or, for example, indirectly throughthermal feedback layer 109). In some embodiments, temperature controllayer 107 may heat and/or cool dispensing chamber housing 425. Sincedispensing chamber housing 425 may be at least partially thermallyconductive, heating or cooling dispensing chamber housing 425 may heator cool a substance 123 (such as a drug to be delivered into an eye 131)located in dispensing chamber 103.

In some embodiments, first processing device 119 may use a feed backloop utilizing information from the thermal sensors to control theoperation of temperature control layer 107. A control algorithm, such asa proportional integral derivative (PID) algorithm with temperatureinformation used as at least one of the inputs, may be used to controlthe operation of temperature control layer 107. In some embodiments,temperature information may be transferred from thermal sensor 115through interface 530, tip interface connector 453, dispensing assemblyinterface connector 553, and interface 535 back to first processingdevice 119.

In some embodiments, thermal sensor 115 may include a resistive devicewhose resistance varies with temperature for providing temperatureinformation to use in controlling the operation of temperature controllayer 107. Thermal sensor 115 may be located on or near dispensingchamber 103 and/or housing 425 to measure a temperature of or neardispensing chamber 103 and/or housing 425. In some embodiments, thetemperature information detected by the thermal sensor 115 may correlateto a temperature of the substance 123 in dispensing chamber 103.Therefore, temperature information for the dispensing chamber 103 and/orhousing 425 may be used to control a temperature control layer 107 toheat/cool the substance 123 located in dispensing chamber 103. If thethermal characteristics of dispensing chamber housing 425 and thesubstance 123 is known, the temperature of temperature control layer 107may be controlled through the temperature control layer 107. Poweringthe resistive element of temperature control layer 107 for a specifiedperiod of time may result in a calculable change in the temperature ofthe substance 123 in dispensing chamber 103.

FIGS. 6 a-6 c are schematic depictions of three different circuitembodiments. FIG. 6 a shows one of many different configurations fortemperature control layer 107. In FIG. 6 a, temperature control layer107 is connected to connectors 452 and 455. Power and/or control signalsmay be provided to temperature control layer 107 through connectors 452and 455. FIG. 6 b shows one of many different configurations for thermalsensor 115. As seen in FIG. 6 b, thermal sensor 115 may be connected toconnectors 451 and 454. Signals may be received from thermal sensor 115through connectors 451 and 454. Many other configurations of connectors451, 452, 453, 454, 455, and 456 may be implemented. For example, whilesix connectors are shown, any number of connectors may be implemented.Further, different combinations of circuits may be contained in a tipsegment 105.

FIGS. 7 a-7 c illustrate circuit diagrams of an embodiment incorporatingan additional thermal sensor (e.g., thermal sensor 117). In someembodiments, a feedback sensor (e.g., one or more thermal sensors)and/or a resistive element (e.g., on temperature control layer 107) maybe coupled to the tip segment 105 through one or more contacts (e.g.,contacts 701 a,b). In some embodiments, the temperature control layer107 and the thermal sensor 115 may be placed proximate to each other(e.g., may both be on the tip segment 105 and in thermal communicationwith each other). Additional thermal sensors (e.g., thermal sensor 117)may also be incorporated in the tip segment 105 and may becommunicatively coupled to a processing device (e.g., processing device119 or 901) controlling the temperature control layer 107. In someembodiments, thermal sensors 115,117 may include 20 k ohm thermistors(other thermistor sizes are also possible (e.g., 5 k ohm, 30 k ohm)).Processing device layout 719 in FIG. 7 a illustrates an embodiment of aprocessing device layout for a processing device (such as processingdevice 119 which may be a PIC 12F683 processor). The additional thermalsensor 117 may add redundancy to the existing thermal sensor 115 and mayprovide additional sources of temperature information for use by theprocessing devices in controlling temperature control layer 107. Theadditional temperature information may be used by the processing devicesto identify a faulty thermal sensor and/or other causes of impedanceoffsets (e.g., accumulated debris on a thermal sensor, an offset betavalue, etc). As another example, a thermal sensor that includes athermocouple with a poor solder joint may have an offset in the voltagebetween the thermocouple's junctions that may generate inaccuratethermal readings from the thermocouple. The additional thermal sensor117 may reduce the effect of any in-series parasitic resistance on avoltage output from a junction of the first thermal sensor 115 (e.g., athermistor) and a load resistance (e.g., the temperature control layer107). The additional thermal sensor 117 may also eliminate single pointfailures in the thermistor sense circuit of the feedback layer 109. Insome embodiments, a processing device may receive temperatureinformation from the two or more thermal sensors 115/117 (e.g.,separately as shown in FIG. 7 b or may receive information on arespective difference (e.g., through sensed current/voltage from lines MVoltage and P Voltage which may be electrically coupled to theprocessor) between the two sensor readings as seen in FIG. 7 c) and maydetermine if the temperature information from the thermal sensors115/117 are within a predetermined tolerance. In some embodiments, thethermal sensors 115/117 may be placed in a bridge configuration (e.g.,see FIG. 7 c) with two or more resistors (e.g., resistors 703 a,b). Theoutput voltage of the bridge circuit may indicate a difference inthermal sensor readings. In some embodiments, the resistors 703 a,b maybe 3000 ohm resistors (in some embodiments, the values of thethermistors used for the thermal sensors 115/117 may approach 3000 ohmsat the desired temperature of operation). Further, using a bridge mayminimize effects from stray resistances in contacts by leveraging thelarger resistances of the bridge. Other resistance values are alsopossible. In some embodiments, the predetermined tolerance may be +/−5degrees Celsius. Other tolerances may also be used. If temperaturesderived from the temperature information are not within thepredetermined tolerance (e.g., if one temperature is indicated as 10degrees higher than the other detected temperature), the processingdevice (such as processing device 119 or 901) may indicate to the userthat there is an error (which may indicate the tip segment 105 needs tobe replaced). In some embodiments, the processing device and/or user mayterminate a procedure (e.g., if the error is detected during a surgery)until a replacement tip segment or handpiece is located.

FIGS. 8 a-8 c illustrate configurations for thermally coupling a thermalsensor 115 or 117 (such as a thermistor) to a hub 809 (which mayinclude, for example, a surface of the chamber 103 or dispensing chamberhousing 425), according to various embodiments. As seen in FIG. 8 b, athermal sensor 115 (or thermal sensor 117) may be mounted onto a flap815 on the same side as the object to whose temperature is beingmeasured. The flap 815 may be held on one side/corner of the temperaturecontrol layer 107 and may give way (e.g., break away or tear) when thetemperature control layer 107 is adhered to the hub's surface. In someembodiments, the thermal sensor 115/117 may be part of a thermalfeedback layer 109 that includes sensory traces (e.g., copper, inconel,etc.) in an insulation material. For example, the one or more thermalsensors 115/117 may be traces insulated by Kapton™ (other insulationmaterials are also contemplated). In some embodiments, the thermalsensors 115/117 may be individual elements that are not in a layerconfiguration. Placing the thermal sensor 115/117 on the flap 815 andfilling a gap between the thermal sensor 115/117 and the flap 815 withthermal glue 811 (a.k.a., thermal adhesive/thermal paste) and/or thermalgrease may decrease an amount of surface area exposed to the colderambient air within the ophthalmic injection device 100. The placement ofthe thermal sensor 115/117 and thermal glue 811 may also eliminate theinsulating layer between the thermal sensor 115/117 and the chamber 103to allow the thermal sensor 115/117 to provide a better approximation ofthe chamber temperature. In some embodiments, the thermal sensor 115/117may be bonded directly to the hot hub 809. While a separate adhesive 807is shown in FIG. 8 b between the thermal sensor 115/117 and the hub 809,adhesive 807 may not be a separate element from thermal glue 811 (e.g.,thermal glue 911 and/or thermal sensor 115/117 may extend to the hub809). In some embodiments, adhesive 807 may be a separate/additionaladhesive. In some embodiments, the adhesive 807 may be an insulatingadhesive or may be a thermal adhesive. As seen in FIG. 8 a, the thermalsensor 115/117 may be fitted into a recess 813 (e.g., a notched recess)in hub 809. As seen in FIG. 8 c, the thermal sensor 115/117 may beplaced between the insulation of the temperature control layer 107 andthe hub 809. Placing the thermal sensor 115/117 in the recess 813 asseen in FIG. 8 a may prevent the temperature control layer 107 fromlifting and creating hot air pocket 805 (which may lead to a lessaccurate temperature reading by the thermal sensor). The temperaturecontrol layer 107 of FIG. 8 a may need alignment between the thermalsensor 115/117 and the recess 813 during manufacturing to insure thethermal sensor 115/117 fits within the recess 813.

FIGS. 9 a-9 c illustrate an embodiment of a thermal feedback layer 109and a temperature control layer 107 for a tip segment 105. In someembodiments, the thermal feedback layer 109 may include a closed loopthermal feedback circuit with temperature sensor circuitry 905 (whichmay include sensor traces for the thermal sensor 115 or 117). Anembodiment of a form factor (i.e., the geometry/shape of the layer) forthe thermal feedback layer 109 is shown in FIG. 9 a. In someembodiments, the temperature control layer 107 may include a resistiveelement 121 (e.g., with multiple resistive traces that convertelectrical current to heat through resistance). An embodiment of a formfactor for the temperature control layer 107 is shown in FIG. 9 b. Invarious embodiments, the temperature sensor circuitry 905 and resistiveelement 121 on the tip segment 105 may interface with the circuitry onthe dispensing assembly through contact/connectors 903 a-f (which maycorrelate to contacts 701 a as seen in FIG. 7 a).

In some embodiments, the sensor traces for a thermal sensor in thethermal feedback layer 109 (e.g., thermal sensor 115/117) may be made ofcopper, silver or gold. These materials may have low resistance and maybe highly adherent to improve bondability of the thermal feedback layer109 in an assembly (which may include the temperature control layer 107and chamber 103). These materials may also reduce parasitic resistancecaused by the sensor traces being smaller in width than the resistivetraces on the temperature control layer 107. The reduced parasiticresistance may also reduce temperature offsets that may affecttemperature information determined using the sensor traces on thethermal feedback layer 109. Other materials are also contemplated (e.g.,inconel). In some embodiments, the thermal feedback layer 109 mayinclude copper traces in a layer of Kapton™ and the temperature controllayer 107 may include inconel traces in a layer of Kapton™. If thesensor traces are made of copper, silver, or gold instead of inconel,the thermal feedback layer 109 may have an improved bondability that mayrequire less adhesive to bond the thermal feedback layer 109 to thetemperature control layer 107 than if both the thermal feedback layer109 and temperature control layer 107 included inconel traces.

In some embodiments, the thermal feedback layer 109 and the temperaturecontrol layer 107 may be manufactured as two separate layers that maythen be bonded together to form a combined assembly 915 a (see FIG. 9c). The combined assembly 915 a may then be wrapped around thedispensing chamber 103 or dispensing chamber housing 425. For example,the thermal feedback layer 109 and the temperature control layer 107 maybe bonded to each other (e.g., through a thermal adhesive) and thecombined assembly 915 a may be wrapped around and bonded to thedispensing chamber 103. In some embodiments, the thermal feedback layer109 and the temperature control layer 107 may be separately wrappedaround the dispensing chamber 103 or dispensing chamber housing 425. Forexample, the thermal feedback layer 109 or the temperature control layer107 may be wrapped around and bonded to the dispensing chamber 103 andthen the other of the thermal feedback layer 109 and the temperaturecontrol layer 107 may be wrapped around and bonded to the dispensingchamber 103 and/or previously wrapped layer. Thermal adhesive, solder,etc., may be used to bond the various layers to each other and/or thechamber 103 to thermally couple the layers to the chamber 103. In someembodiments, integrated circuits (e.g., forming a second processingdevice 901) may also be bonded to one or more of the thermal feedbacklayer 109 and the temperature control layer 107 (e.g., through solder).In some embodiments, the integrated circuits may not require adhesive inaddition to the solder.

FIGS. 10 a-c illustrate an embodiment with different form factors forthe thermal feedback layer 109 and temperature control layer 107 of thetip segment 105. In some embodiments, the individual form factors of thethermal feedback layer 109 and/or temperature control layer 107 may bereduced to increase the flexibility of the layers 107/109 and/orcombined assembly 915 b. As seen in FIG. 10 a, the thermal feedbacklayer 109 may include a form factor with a reduced resistive element tabportion 1001. In some embodiments, the temperature control layer (seeFIG. 10 b) may not include an IC tab portion 1003 in the temperaturecontrol layer form factor. These reduced form factors may increase theflexibility of each layer with respect to the other layers to improvebondability of the layers to each other and to the dispensing chamberand to improve the flexibility of the combined assembly 915 b (improvedflexibility versus if each layer had the same complete form factor).FIG. 10 c illustrates an embodiment of combined assembly 915 b with thethermal feedback layer 109 shown in dashed lines. In some embodiments,the reduced form factor layers may be easier to wrap around the chamber103 or dispensing chamber housing 425 separately to form the combinedassembly (which may improve manufacturability of the layers). Other formfactors and form factor configurations are also contemplated. Forexample, other areas of the thermal feedback layer 109 and thetemperature control layer 107 that do not have, for example, circuitryelements, may be removed or reduced. In addition, elements of the layersmay be rearranged and non-used areas may be removed or reduced.

FIGS. 11 a-b illustrate an embodiment with a second processing device901 (e.g., located on tip segment 105) to receive temperatureinformation from a first thermal sensor 115. In some embodiments, thesecond processing device 901 may convert signals from the first thermalsensor 115 (e.g., signals such as a change in voltage, current,resistance, etc. that is indicative of a change in temperature) to afirst processing device 119 (e.g., on dispensing assembly 111). In someembodiments, a first thermal sensor 115 may be monitored by a secondprocessing device 901 (which may be a PIC10/12 microprocessor) local tothe temperature control layer 107. The second processing device 901 mayreceive signals (e.g., analog signals) from the first thermal sensor 115and may analyze/convert these signals before communicating with thefirst processing device 119. For example, the second processing device901 may send digital signals with temperature information (e.g., fromthe first thermal sensor 115) to the first processing device 119. Thefirst processing device 119 may also receive other temperatureinformation (e.g., as an analog signal from a second thermal sensor 117as discussed above with respect to FIGS. 7 a-b). In some embodiments,both signals (from the first and second thermal sensors) may be digital(or both may be analog). The first processing device 119 may compare thetemperature information from the second processing device 901 and thetemperature information received from the second thermal sensor 117 todetermine if there is an offset between the temperatures detected by thethermal sensors (or, for example, between detected voltages indicativeof temperature). Using temperature information from two differentthermal sensors may allow the first processing device 119 to detect anin-series parasitic resistance located on the power, ground, or thermalsensor contact lines (e.g., thermistor contact lines) that may cause adiscrepancy between the two signals (e.g., the digital signal and theanalog signal). The first and/or second processing devices may try tocompensate for the discrepancy if the discrepancy is small (such as <5degrees Celsius) (e.g., by controlling/adjusting the resistive element121 of the temperature control layer 107 using an average of thetemperatures indicated by the first and second thermal sensors) or mayindicate an error and/or shut down the ophthalmic medical device 100.

In some embodiments, the thermal sensors and/or second processing device901 may communicate with first processing device 119 at least in partthrough connectors/contacts (e.g., between the tip segment 105 and thedispensing assembly 111). Connectors/contacts (e.g., connectors/contacts701 a,b and 903 a-f) may be incorporated at least partially in thedispensing assembly interface connector 553 (other locations are alsocontemplated).

In some embodiments, first processing device 119 may be communicativelycoupled to a memory 1050 (which may be an embedded/on-chip memory and/ora memory external to first processing device 119). Other locations forthe memory are also contemplated (e.g., as an on-chip memory to secondprocessing device 901). In some embodiments, the memory may be a staticmemory and the information on the memory 1050 may be accessed digitally.The memory may hold information such as number of times the tip segment105 has been used, a temperature set point (e.g., a desired temperatureto heat the drug to), drug delivery speed, drug density, drug thermalcoefficients of expansion, etc. By storing the number of uses on thememory 1050, this information may be used to determine whether to allowthe tip segment 105 to function (e.g., the tip segment 105 may beprevented from functioning if the number of uses exceeds a predeterminedthreshold (e.g., 1 use)). Using a memory may eliminate the need for ahigh current circuit/fuse (although, a fuse 601 may be also be used).Information stored on the memory 1050 may also be used in the operationof the tip segment 105 and/or dispensing assembly 111 (e.g., set-pointtemperature, expel velocities, volumes and disposable tipidentification, etc). In some embodiments, a programming/debugging pin1101 may be used to store information onto the second processing device901 (e.g., onto an on-chip memory of second processing device 901)and/or to program the second processing device 901. For example, anexternal device such as a computer system may couple to theprogramming/debugging pin 1101 to interface with the second processingdevice 901 (and/or memory accessible to the second processing device901).

FIG. 12 illustrates a flowchart of an embodiment of a method forinjecting a substance 123 into an eye 131. The method of FIG. 12includes activating the temperature control layer 107 to heat or coolthe substance 123 located in the dispensing chamber 103. The elementsprovided in the flowchart are illustrative only. The provided elementsmay be omitted, additional elements may be added, and/or variouselements may be performed in a different order than provided below.

At 1205, a connection between a tip segment 105 and a dispensingassembly 111 may be recognized. For example, processing device 119 maysend and/or receive signals from the tip segment 105 throughconnectors/contacts 701 a,b and/or 903 a-f. In some embodiments,components of tip segment 105 (such as processing device 901) may sendsignals to the processing device 119 when the tip segment 105 is coupledto the dispensing assembly 111.

At 1210, the type of tip segment 105 may be identified. For example,information may be stored on memory 1050 as to the type (e.g., singleuse, limited reuse, etc.) of tip segment 105 and this information may bepassed to the processing device 119 when the tip segment 105 is coupledto the dispensing assembly 111.

At 1215, dosage information may be received from the tip segment 105.For example, dosage information (e.g., volume, dispense rate, etc.) maybe stored on memory 1050 and be passed to the processing device 119 whenthe tip segment 105 is coupled to the dispensing assembly 111.

At 1220, a temperature control layer 107 may be activated to alter atemperature of a substance 123 contained in the dispensing chamber 103.In some embodiments, the temperature control layer 107 may be charged byan internal power source and/or may be charged by an external chargingstand.

At 1225, temperature information (e.g., a change in voltage, current,resistance, etc. that is indicative of a change in temperature) may bereceived from a thermal sensor (such as thermal sensor 115 and/or 117).As another example, temperature information may be received in the formof a voltage or current detected from a bridge that includes the firstand second thermal sensor (e.g., see FIG. 7 c).

At 1230, the temperature information may be used to control thetemperature control layer 107. For example, the processing device 119may signal temperature control layer 107 to provide current to theresistive element 121 until a set temperature is indicated by one ormore thermal sensors.

FIG. 13 illustrates a flowchart of an embodiment of a method foroperating the tip segment 105 and dispensing assembly 111 for injectinga substance 123 into the eye 131. The elements provided in the flowchartare illustrative only. The provided elements may be omitted, additionalelements may be added, and/or various elements may be performed in adifferent order than provided below.

At 1305, a user may connect the tip segment 105 to a handpiece (e.g., areusable handpiece including the dispensing assembly 111).

At 1310, the tip segment 105 (e.g., second processing device 901 on tipsegment 105) may transmit information to the dispensing assembly 111(e.g., to first processing device 119). The information may include packidentification (ID) (identifying a package the tip segment 105 wasdelivered in), procedural parameters (e.g., temperature set point, drugdelivery speed, drug density, drug thermal coefficients of expansion,etc.), and number of prior uses (or, for example, information indicatingthat the tip segment 105 has not been used prior).

At 1315, the pack ID and additional information may be verified (e.g.,by the first processing device 119 on the dispensing assembly 111). Ifthe number of prior uses exceeds a predetermined threshold or if theinformation received (or not received) indicates a problem (e.g., doesnot fall within predetermined ranges), the dispensing assembly 111(e.g., the first processing device 119) may indicate that the tipsegment 105 should not be used. For example, if the ophthalmic injectiondevice 100 is a limited reuse assembly and information stored in thememory 1050 indicates the tip segment 105 has been used more than apredetermined threshold (e.g., 1 time), the first processing device 119may transmit a command to the second processing device 901 to shut downthe tip segment 105 and/or prevent the tip segment's use.

At 1320, the tip segment 105 may transmit temperature information. Forexample, the second processing device 901 may monitor a first thermalsensor 115 and may send information indicative of temperatureinformation received from the first thermal sensor (e.g., in digitalform) to first processing device 119. Additional temperature information(e.g., from a second thermal sensor) may be transmitted to the firstprocessing device 119 directly (e.g., in analog form (or digital form)).

At 1325, the temperature information from the first thermal sensor 115and the second thermal sensor 117 may be compared to determine if theindicated temperatures are within tolerance of each other (e.g., within+/−0.5 degrees, +/−1 degrees, +/−5 degrees, +/−10 degrees, etc). In someembodiments, the temperature information may be separately compared topredetermined thresholds instead of being compared to each other. Othercomparisons are also contemplated. For example, as seen in FIG. 7 c,information (e.g., relayed through a detected voltage or current) from abridge circuit including the first and second thermal sensor may beindicative of a difference between the two sensors.

At 1330, the tip segment 105 may be allowed to heat or cool a substance123 in the dispensing chamber 103 and the temperature information fromthe first and second thermal sensors may continue to be monitored. Ifthe detected temperatures are not found to be within a tolerance of eachother or separately within a predetermined range, the tip assembly 105may be instructed not to initiate heating or cooling a substance 123 inthe dispensing chamber 103 and/or the tip assembly 105 may discontinueheating or cooling substance 123 if the heating/cooling process hasalready started. In some embodiments, an error may be indicated if thedetected temperatures are not within a tolerance. If the heating/coolingsequence had started, a use of the tip segment 105 may be indicated on amemory 1050 accessible by the second processing device 901 and/or firstprocessing device 119 at startup. The indicated use may prevent the tipsegment 105 from being used again in the future.

FIG. 14 illustrates an embodiment of coupling the dispensing chamberhousing 425 to an outer support 1401. In some embodiments, the outersupport 1401 may be an elastomer support (other materials such as metalmay also be used) that is separately coupled inside the tip housing 215.The dispensing chamber housing 425 may include a bell-shaped end 1403that secures the end of the dispensing chamber housing 425 inside thesupport 1401. For example, one end of the dispensing chamber housing 425may fit through the outer support while the bell-shaped end 1403 mayhold the dispensing chamber housing 425 in place (e.g., through afriction fit (or, for example, through adhesive) with the support 1401.The dispensing chamber housing 425 may be coupled inside the support1401 using other mechanisms (e.g., adhesives, fasteners, ultrasonicwelding, etc).

FIG. 15 illustrates another embodiment of the thermal feedback layer1507. In the embodiment shown in FIG. 15, the thermal feedback layer1507 may not include a processing tab segment holding second processingdevice 901. For example, the processing device 901 may be included onthe tab portion 1505 (or may not be included). In some embodiments, thethermal sensors 115/117 may be placed further apart on the thermalfeedback layer 1507 and two windows 1501/1503 may be provided (one foreach thermal sensor) for the wrap around (see FIGS. 16 a-d). Thecircular contact portion may include contacts 903 a-f on one layer tointerface with corresponding contacts on the lower dispensing assembly111 e (which, as seen in FIG. 16 d, may include multiple correspondingcontacts). In some embodiments, the lower dispensing assembly 111 e mayinclude six corresponding interface connectors 1653 a-f (see exampleinterface connector 553 and example dispenser assembly components inFIG. 5). Other configurations are also possible (e.g., data from the sixconnectors may be placed through a single connector interface with thelower dispenser assembly).

FIGS. 16 a-d illustrate an example of assembling the thermal feedbacklayer 1507 into the dispenser assembly. As seen in FIG. 16 a, the tabportion 1505 of thermal feedback layer 1507 may be wrapped around thedispensing chamber housing 425 such that a thermal sensor 115/117 linesup on alternate sides of the dispensing chamber housing 425 and windows1501/1503 line up with their corresponding thermal sensor 115/117 suchthat each thermal sensor 115/117 protrudes through respective windows1501/1503. In some embodiments, the bottom of the thermal feedback layer1507 may be coated with an adhesive. In some embodiments, a backing maybe peeled off of the thermal feedback layer 1507 to expose the adhesiveprior to wrapping the thermal feedback layer 1507 on the dispensingchamber housing 425. Other fasteners are also contemplated (e.g., clips,welds, etc). As seen in FIG. 16 b, the thermal feedback layer 1507 maybend along a contour of the support 1401. As seen in FIG. 16 c, thecircular contact portion may also bend to attach to the back of thesupport 1401 to align the contacts 903 a-f with corresponding connectors1653 a-f (which may themselves be contacts) on the dispensing assembly111 e. In some embodiments, contacts 903 a-f may be electricallyconnected to various components on the thermal feedback layer 1507(e.g., the thermal sensors 115/117) through electrical linesembedded/deposited on the thermal feedback layer 1507. In someembodiments, electrical signals may travel through the contacts 903 a-fand connectors 1653 a-f to allow the dispenser 111 e to communicate withthe components of the thermal feedback layer 1507 (or other layers suchas the temperature control layer 107 which may also communicate throughcorresponding contacts (e.g., contacts 903 e-f shown in FIG. 9 b)). Asseen in FIG. 16 d, the dispensing chamber housing 425 may be insertedinto tip assembly 215 which may be coupled to the dispensing assembly111 e (to mate connectors 1653 a-f and contacts 903 a-f). As seen inFIG. 2, in some embodiments, the tip assembly 215 may be screwed ontothe dispensing assembly 111 e (other attachment mechanisms are alsocontemplated).

In some embodiments, the tip segment 105 and/or dispensing assembly 111may include one or more processing devices (e.g., first processingdevice 119, second processing device 901, etc). In various embodiments,the processing devices may include integrated circuits with power,input, and output pins capable of performing logic functions. Forexample, first processing device 119 may be a targeted device controllerthat performs specific control functions targeted to one or more devicesor components, such as temperature control layer 107 or power source505. In some embodiments, first processing device 119 may directlycontrol temperature control layer 107 or may interface with anotherprocessing device (such as a temperature control layer controller on thetemperature control layer 107) to control the basic functionality of thetemperature control layer 107. While depicted as one component invarious FIGs., processing devices (such as first processing device 119,second processing device 901, etc.) may each be made of many differentcomponents or integrated circuits. For example, each processing devicemay include a single processing device or a plurality of processingdevices.

The processing devices may include a microprocessor (e.g., aprogrammable microprocessor), controller (such as a micro-controller orother special purpose controller), digital signal processor,microcomputer, central processing unit, field programmable gate array,programmable logic device, state machine, logic circuitry, controlcircuitry, analog circuitry, digital circuitry, and/or any device thatmanipulates signals (analog and/or digital) based on operationalinstructions. A memory coupled to and/or embedded in the processingdevices may be a single memory device or a plurality of memory devices.Such a memory device may be a read-only memory, random access memory,volatile memory, non-volatile memory, static memory, dynamic memory,flash memory, cache memory, and/or any device that stores digitalinformation. Note that when the processing devices implement one or moreof its functions via a state machine, analog circuitry, digitalcircuitry, and/or logic circuitry, the memory storing the correspondingoperational instructions may be embedded within, or external to, thecircuitry comprising the state machine, analog circuitry, digitalcircuitry, and/or logic circuitry. The memory 1003 may store, and theprocessing devices may execute, operational instructions correspondingto at least some of the elements illustrated and described inassociation with the figures.

Various modifications may be made to the presented embodiments by aperson of ordinary skill in the art. For example, although some of theembodiments are described above in connection with surgical handpieces,it can also be used with other surgical devices utilizing a heaterelement. Other embodiments of the present invention will be apparent tothose skilled in the art from consideration of the present specificationand practice of the present invention disclosed herein. It is intendedthat the present specification and examples be considered as exemplaryonly with a true scope and spirit of the invention being indicated bythe following claims and equivalents thereof.

1. An ophthalmic injection device, comprising: a dispensing chamberconfigured to hold a substance to be injected into an eye; a thermalfeedback layer comprising at least one thermal sensor; a temperaturecontrol layer configured to apply or remove heat from the dispensingchamber; wherein the thermal feedback layer and the temperature controllayer are coupled to the dispensing chamber, wherein each of the thermalfeedback layer and the temperature control layer are flexible andconfigured to at least partially wrap around the dispensing chamber. 2.The ophthalmic injection device of claim 1, wherein the thermal feedbacklayer and the temperature control layer have an identical form factor.3. The ophthalmic injection device of claim 1, wherein the thermalfeedback layer has a form factor that includes a thermal sensor on afirst tab and a microprocessor on a second tab connected to the firsttab.
 4. The ophthalmic injection device of claim 3, wherein thetemperature control layer comprises resistive traces on a third taboriented to overlap the first tab of the thermal feedback layer when thethermal feedback layer and the temperature control layer are coupled tothe dispensing chamber.
 5. The ophthalmic injection device of claim 4,wherein the temperature control layer does not have a tab correspondingto the second tab of the thermal feedback layer.
 6. The ophthalmicinjection device of claim 1, wherein the thermal feedback layercomprises traces made of copper, silver, or gold and the thermalfeedback layer comprises traces made of inconel.
 7. The ophthalmicinjection device of claim 1, wherein the thermal feedback layer and thetemperature control layer are configured to be bonded together to formone assembly that is configured to be wrapped at least partially aroundthe dispensing chamber.
 8. The ophthalmic injection device of claim 1,wherein the dispensing chamber comprises a first end face, a second endface, and a side face coupling the first end face and the second endface, and wherein at least one of the thermal feedback layer and thetemperature control layer are configured to cover more than 50 percentof the side face.
 9. An ophthalmic injection device, comprising: adispensing chamber configured to hold a substance to be injected into aneye; a temperature control layer configured to couple to a thermalsensor, wherein the thermal sensor is coupled between the dispensingchamber and the temperature control layer; and wherein the temperaturecontrol layer is coupled to the dispensing chamber and configured toapply or remove heat from the dispensing chamber.
 10. The ophthalmicinjection device of claim 9 wherein the temperature control layercomprises a flap and wherein the thermal sensor is coupled between theflap and the dispensing chamber through a thermal adhesive.
 11. Theophthalmic injection device of claim 9, wherein the thermal sensor iscoupled between a recess in the dispensing chamber and the temperaturecontrol layer, and wherein the thermal sensor is at least partiallyinside the recess.
 12. The ophthalmic injection device of claim 9,wherein the temperature control layer is wrapped over the thermal sensorcreating a bump in the temperature control layer where the thermalsensor is coupled between the dispensing chamber and the temperaturecontrol layer.